1. Field of the Invention
The present invention relates to a push button switch mechanism; more specifically, the invention relates to a scissors-type push button switch having slanted surfaces above the bearing slots integrated into the surface of the base plate. The slanted surfaces are designed so that lateral cylindrical protrusions located at free ends of a linking bracket can be snapped into the bearing slots with a single push towards the base plate.
2. Description of Related Art
FIG. 1 shows an exploded view of a push button switch having scissors-type arm members disclosed in Taiwanese Patent NO. 86,200,053 and U.S. Pat. No. 5,746,308.
As illustrated in FIG. 1, a push button switch of prior art comprises a first linking bracket 17 having two arm elements 171, wherein a lateral cylindrical protrusion 174a is located at the end of each arm element. Each of the two lateral cylindrical protrusions 174a faces outwardly and is fixed in place by insertion into the bearing slots 183 formed by bending out parts of base plate 18 into an upright position above the surface 185.
When lateral cylindrical protrusions 174a of the two arm elements 171 are to be inserted into the bearing slots 183, an external force has to be exerted laterally on the outward surface of each of the arm elements 171 to decrease the distance between the two cylindrical protrusions 174a. The two cylindrical protrusions 174a are inserted into the bearing slots 183 while being squeezed and then released to click into position. This squeezing and releasing adds complexity to the assembly process, increasing the overall manufacturing cycle time for each push button assembly.